Continuity of a power-series function

chi8
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Homework Statement



Prove the function:
g(x)=\sum_{n=1}^{\infty }\frac{1}{^{n^{0.5}}}(x^{2n}-x^{2n+1})

is continuous in [0,1].2. The attempt at a solution

I tried to look at this functions as:

g(x)=(1-x)\sum_{n=1}^{\infty }\frac{1}{^{n^{0.5}}}x^{2n}

but I couldn't find a way solving it from here.
Finding the radius of convergence (which is 1) didn't help a lot...
 
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Yes, writing it as
$$g(x) = (1-x) \sum_{n=1}^\infty \frac{1}{n^{0.5}} x^{2n}$$
is a good start. Let us introduce the notation
$$p(x) = \sum_{n=1}^\infty \frac{1}{n^{0.5}} x^{2n}$$
This is a power series. If its radius of convergence is 1, do you know a theorem which tells you that p is continuous on (-1,1)? If so, then you only need to worry about the point x = 1. Does the series converge at x = 1?
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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